Safety device for pneumatic hammers.



lC. E'. MCDQNALD, SAFETY wwwL I; FOR PNEUMATIG HAMMERS.

APPLICATION FILED JUL-1717,. 1913'.

Lmmfm UMTED 'STATES PATENT onirica,

crimes F.IoDoNALD, or PHILADELPHIA, PENNSYLVANIA, AssIeNon or ONE-Herr 'ro ,JOHN B. MUNjrz, or PHILADELPHIA, Pennsylvanie. i

SAFETY DEVICE FOR PN'EUMATIC BANKERS.

To all 'whoml it concern.'

Be it known that I, CHARLES F. MoDoN-v lALD, a citizen of the UnitedStates, residing at lPhiladelphia, -in the county of Philadelphia andl State of Pennsylvania, have inlvented lnew` andr useful' Improvements in SafetyDevices for`Pneumatic Hammers, of which' the followin is a, specification.v

This inventionre ates to improvements 1n pneumatic hammers, and the primary object of the invention isto provide a safety device WhichWill prevent opening of the throttle of the hammer` exceptwhen manipulated by lthe hand ofthe operator, that is to say, the throttlemperating lever cannot-be accidentally"o-p'e'ra'tec'lby the striking of the f oot or any other objectr against the same while the hammeris' lying upona scaffold or other support, experience having shown that hammers as heretofore constructed, when started, accidentally caused .the rivet-set or other tool used in the end thereof to be discharged from the `'hammer with serious consequences to thejoper'ator orto persons working in the vicinity.` v

The automatic safety device provided'by the present vinvention is very simple in its construction, it is capable of being applied readily to hammers of the types now gener- Fig. 2 is a top plan view of theh'ammer as shown in'Fig. 1; Fig. 3 is an end view ofthe hammer looking toward thc handle end thereof. n

Similar parts vare designated by the same reference characters in the several views.

The present inventionis applicable generally to pneumatic hammers of the types now in use andin the present instance it is `shownin connection with a hammer of the well known'type which embodies a barrel or specification' of Leners raten.

Application led July 17, 11913` Serial-No. 779,594. l

Patented June 23, tte,

.cylinder .1 Which'contains the reciprccatory piston and a handle 2, .the latter having` a grip portion 3 to be engaged by the hand of the operator whereby the hammer` is held in proper position during its operation. The handleportion of the hammer has an inlet connection 4 through which the motive fluid is supplied and a passageway 5 through which the motive fluld flows to the reciprocatory piston of the hammer. It is common 'to provide a throttle valve'to control the operation Vofthe hammer by governing the flow lofmotive fluid from the inlet 4 to the passage 5.V In the present instance a bushing 6 is fitted into the rip portion of the handle, thisbushing having ports .7 through which the motive iuid is adapted 'to iiow from the inlet 4C to the interior of the bushing, andthe bushing is also provided with 'ports 8 through which the motive finid is adapted to iow from the inside of the bush ing outwardly and into the passageway' 5 leading to the piston. The valve in the construction shown is adapted to move axially within the bushing, it having heads or pistons 9 and A10 which tit closely within the kbushing and an intermediate fiuted portion 11 which, when the valve is moved in one direction, will extend between the ports and 8 and thereby establish communication be'- tween them whereby motive liuid may flow from thev inlet 4 to the 1passageway 5. Nor inally, however, the lwer'head or, piston 9 on the valve will lap over and close the ports 7, thereby preventing the flow of motive fluid from the inlet 4 into the bushing. A compression spring l2 is provided to operate on the lower end of the valve and thereby maintain Ait in normally closed position. The valve is operated by a member adapted to be manipulated by the thumb of the operator while the grip portion of the handle is grasped by the hand. In the present instance, this valveoperating member is in the form of a lever' 13 which is pivoted at i4 in a slot v15 formed in the grip portion of the handle, the lever having la projection ld which is adapted to bear upon the upper end of the throttle valve whereby when .the uoper end of the lever I3 is pushed forwardly by the thumb 'of the operators hand the..

throttle valve will be moved downwardly against the compression of the spring 12 and the ymotive Huid will then be admitted to the piston of the tool. The construction just described is commonly used upon pneumatic 1 I n hammer' havmgiafthrottlevalveand a .con-

tools of this type. v i y. Y.

The present invention provides an automatic safety device which will the tool is This automatic safety device in the present instance embodies a thumb-piece 17 which is vattached to a pair of arms 18, the latter` Vstr'addling the upper or free end of the lever 'i or member 13 and being ypivoted thereto by sprin 'feXtend th-rou h a pin 22 arran ed" ated" in'.

fthe pin" 19. The arms 18 are adapted. to 'engage'in notches 2O formed in the adjacent normally retain the 'safety the armslS, the spring near-'t e free ends of the safety deacting in a direction to draw vice into position to engage the notches`20.-y

The automatic safety device constitutes in effect a', trigger which must be released by the thumb of the operator-before the throt tlc-operating lever rvmember can be actuorder /to' 'start the 'hammerinto peratien, it isfonly lnecessary for the tor to grasp-the; grip portion'of the handle in the usal Wayand to press the thumb forwardly against-the thumbqoiece 17 of the trigger, 'the latter being then tilted in a direction toy disengage the arms `18 from the notches 20 whereuponV the lever or member th'iottle in the usual Way. When, however, ththrottle is 'closed the spring Will operate automatically to engage the trigger 1n the notches 20 ahd to retain the trigger .in this. position, the 'throttle-operating lever or member 13 at this time being locked from prevent oper# 'ation ofthe lever or member 13 to open 'the "throttle valve except when Igrasped by the hand of the operator .andsaid lever or member is unlocked or released.

and a spring is provided in locked engagement with they operaoperation and the throttle cannot be opened by the striking of any object against it.

I claim as my invention 1.Y 'Ille combination ,with a pneumatic trolling member therefor, of a trigger carried by said memberl forl preventingopera-.

tionthreof nd, for actuating said member when released.

y 2.4 The combination f with a neumatic hammer having a throttle-operating member, and a trigger carried bysaid member and no rmallyoperative to prevent valveopening movement thereof, said trigger constituting means for when released.

e: The' i Combination wier 'planmatig actuating W said,` member hammer; having a :throttle-operating member,

and a safety ldevice carried 'by member andpe'rative automatically to 'pre-' vent operation thereof, said device having a thumb-'piece'forreleasing it andjor 'operatiing said member."

4. The"combin`a`tin hammer having"a throtle-.operatingf lever,

of a. trigger Imvoted .thereon and havin a "portion'to engage the yhammer""handle 'te lock said iever from operation, a. springfor normally holding the trigger in locked posi tion,` and a thumbrpiece forreleasing theltrigger and operating thelever.

5. The combination with a Apneunviatict` ber, of a trigger ofxyokeshape straddling hammer providedwith a uhandle having a., notc'htherein and a throttle-operating mem7 y.

and pivotedfon said member, vand aspring.. v.

operative on s'aid trigger to engage itin saidl notchon- .the handle, the trigger. having a thumb-piece which when depressed disen-v gages theztrigger from said'notch and. moves said member into throttle-,opening position.

tion.

In Itestimony whereof I .have hereunto set F, MCDON'ALD `'my hand in presence of two subscribing witmesses y Y 

